1. Field of the Invention
The present invention generally relates to an optical system, and more particularly to an optical system including multiple lens groups having a reduced volume.
2. Description of the Related Art
An optical imaging system includes imaging elements such as CCD imaging elements (charged coupled devices) or CMOS imaging elements (complimentary metal oxide semiconductors) and at least one lens group for use in various types of consumer products such as digital and monitoring cameras, personal computers, and the like.
The lens group typically includes at least one lens having undesirable aberration characteristics. These undesirable aberration characteristics are intrinsic to the lens and are generated due to the shape of the lens. The aberration characteristics can cause distortion of images in certain circumstances. Among the different type of aberrations, the spherical and coma aberrations, in particular, cannot be easily corrected and can cause image flares and other undesirable visual effects.
In order to solve problems caused by such lens aberrations, it has been previously proposed in the prior art to utilize a lens group including an aspheric lens for correcting the aberrations, or a thin film filter or an optical filter having a sharp surface which can restrict a portion of the light.
Further, recent developments in image devices for miniaturization and portability, for use in miniaturized optical imaging systems require mounting in the image devices.
Therefore, it would be desirable to have an improved optical imaging system that is miniaturized and whose optical characteristics exhibit minimal deterioration over time.